Protective score shield for easy opening container

ABSTRACT

This disclosure relates to an easy opening container of the type wherein one end has an easy opening end closure including a removable panel portion defined by a score line. The end closure includes pliable band superimposed over the score line and attached to either one or both of the inner or the outer faces of the end closure. Upon removal of the removable panel portion, the band attached to the inner face provides a protective ledge for the raw metal edge about the opening and the band attached to the outer face provides a protective ledge for the removed panel portion.

United States Patent 1 91 Kehe 1 May 7, 1974 [54] PROTECTIVE SCORE SHIELD FOR EASY 3,527,377 9/1970 Colly et al. 220/54 OPENING CONTAINER [75] Inventor: Alfred W. Kehe, Berkley, [11. Primary Examiner-George T. Hall [73] Assigneez Continental can p y Inc. Attorney, Agent, or FirmD1ller, Brown, Ramik &

New York, NY. Wight [22] Filed: July 20, 1972 [21] Appl. No.: 273,371 [57] ABSTRACT Related APplicafion Dam This disclosure relates to an easy opening container of [63] Continuation of Ser. No. 151,381, June 9, 1071, the type wherein one end has an easy opening end cloabandoned, which is a Continuation-impart sure including a removable panel portion defined by a abandmed, Whlch a score line. The end closure includes pliable band sui g z g 'g 826966 May perimposed over the score line and attached to either 96 a an one one or both of the inner or the outer faces of the end closure. Upon removal of the removable panel porfi T 220/ tion, the band attached to the inner face provides a i 54 906 protective ledge for the raw metal edge about the le 0 can opening and the band attached to the outer face provides a protective ledge for the removed panel por- [56] References Cited on UNITED STATES PATENTS 3,744,6 7/1973 .Bartels 220/54 14 Claims, 7 Drawing Figures INVENTOR ALFRED W KEHE ATT'Y.

PATENTEDI 7 I974 sum 1 nr 3 I and H .n

\- asQ zz INVENTOR 4 ALFRED w KEHE BY 243M ATT'Y opening container of the full panel opening type.

Full opening containers of the type to'which the present invention relates include a metal end closure of which the end panel is formed with a weakening line located closely adjacent and substantially concentric to the chuck wall. The weakening line is formed by scoring and defines a removable panel portion to which a pull tab is attached. The pull tab is mounted so that upon initial lifting thereof the nose penetrates the weakening line to initiate'the severance of the removable panel portion from the end panel. Thereafter, the pull tab is pulled upwardly so that the remainder of the weakening line is ruptured and the removable panel portion separated from the remainder of the panel substantially in the form of a disc.

The opening formed in the end closure is bounded by the remainder of the end closure panel in the form of a horizontal ledge. The horizontal ledge terminates in a sharp edge resulting from the severance of the removable panel portion therefrom along the weakening line. The sharp edge is somewhat objectionable because it may cause injury by cutting the user or otherwise damaging an article which may be inserted through the opening thus formed. 7

By the present invention, it is proposed to provide a full opening easy opening container having a pliable protective ring or band which is attached to the under-.

side of the metal end closure so as to spanthe weakening line and remain attachedto the horizontal ledge after removal of the removable panel therefrom, and of sufficient hardness to provide a protective edge projecting beyond the raw edge.

It is a further object taken in conjunction with the foregoing proposed easy opening container to provide a flexible pliable band which is made of a pliable material so as to minimize the resistance against the deflection of the removable panel downwardly into the container during the initial rupturing of the weakening line. It is still a further object taken in conjunction with the foregoing objects to provide a protective band spanning the weakening line and which serves to provide a protective barrierto protect the weakening line from corrosion which may result from the product contained in the container.

Moreover, the removable panel portion also has a sharp edge which may cut the user during removal from the container end. This sharp edge is also a hazard when the removable panel portion is discarded as, for example, in public places such as beaches or the like.

Accordingly, when the product or container use so dictates it may be desirable to also provide a pliable band to the upper side of the end closure for removal with the removable panel portion. The upper pliable 2 band is attached similarly to the lower pliable band and is arranged to project beyond the edge of the removable portion and provide a protective edge. Under some circumstances, the conditions may be such that only an upper pliable band be used to protect the edge of the removable panel portion.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description and the several views illustrated in the accompanying drawings.

In the Drawings:

FIG. 1 is a top plan view of an end closure embodying the structure of the present invention.

FIG. 2 is a bottom plan view of the end closure with some of the parts being broken away to show underlying details of structure.

FIG. 3 is a cross-sectional view of the end closure applied to a container body and showing the structure-of the present invention when the container end is intact.

FIG. 4 is a fragmentary cross-sectional view similar to FIG. 3 but showing the condition of the protective lip upon initial rupturing of the weakening line.

FIG. 5 is a fragmentary view showing the condition 'of theprotective ledge after the removable panel portion has been removed.

FIG. 6 is a fragmentary cross-sectional view of a container showing an edge protective band also applied to the upper face of the end closure for removal with the removable panel portion.

FIG. 7 is a fragmentary cross-sectional view of a container showing a thermosetting base coating applied to the entire underside face of the end panel to which a subsequently applied enamel coating is adherent but to which the protective band is nonadherent.

Referring now to the drawings, there is illustrated a container or can 10 including a body 11 of which only the upper portion is illustrated. The lower portion of the body 11 is closed in the conventional manner by an end closure, not shown. The upper end of the body 11 is closed by means of an easy opening end closure 12 made from metal and which issecured to the body 11 by means of a conventional double seam 13.

The metal end closure 12 includes the usual chuck wall 14 and an end 'panel 16. The end 12 is of a conventional full opening type and the end panel 16 is provided with a peripheral score line 17 defining a removable panel portion 18 which constitutes a major portion of the end closure 12.

In order to facilitate initial rupture of the panel 16,,

the removable panel portion 18 is provided with an integral rivet 19 by means of which a pull tab 21 is secured thereto. The pull tab 21 is utilized to initially 'place a downwardly or inwardly directed force on the removable panel portion 18 along a starting portion of the score line 17 sufficient to affect the initial rupture of the removable panel portion from the panel 16. A further movement of the pull tab 21 will result in folding or bending of a part of the removable panel portion 1-8 downwardly into the interior of the can 10. Thereafter, an upwardly or outwardly directed pull on the pull tab 21 is effective to completely tear out the removable panel portion 18 along the score line 17.

The can 10 as described above is deficient because of the fact that the raw edge resulting from the tear out of the removable panel portion 18 remains exposed. Thus, if a user inserts his hand into the opening to remove the contents thereof or inserts an object such as the-pipe orthe like in the opening, there is a possibility of injury by cutting the hand or scratching of the object inserted inthe open end.

In accordance with the present invention, this deficiency in one form is overcome by the provision of a flexible pliable ring or band member 22 which is attached to the underside of the end closure. The band 22 is preferably made from a plastic material which may be flowed as a liner in the form of an annular ring 22 on the underside of the end closure 16. To this end, the annular ring 22, in accordance with the present invention, is made from a plastisol composition.

Conventionally, the underside of the metal end closure 16 is provided with an enamel coating 24 made from a thermosetting and thermoplastic resin. The coating as more fully to be explained hereinafter is usually applied to the metal sheet prior to forming the end closure 16 described above.

Typical thermosetting resins which may be employed in the enamel coating include epoxy resins of the type which are polymeric reaction products of polyfunctional halohydrins with polyhydric phenols.

Thermoplastic resins which may be employed in the enamel coating include the vinyl chloride polymer resins, such as polyvinyl chloride, vinyl chloride/vinyl acetate copolymers, vinyl chloride/vinylidene chloride copolymers, .vinylchloride/alkyl maleate copolymers, vinyl chloride/acrylonitrile copolymers, vinyl chloride/- vinyl acetate/maleic anhydride terpolymers, and the like. These thermoplastic resins may be used in combination with any of the thermosetting resins to prepare a suitable enamel coating.

For application to metal surfaces, the abovedescribed resins or mixtures of these resins are dissolved in suitable solvent systems, such as organic ketones, such as methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, and aromatic hydrocarbons, such as xylene and toluene, and mixtures thereof, to provide a coating solution of the necessary viscosity for application to the metal surfaces.

The enamel coating compositions are applied as a liquid solution to the metal surface, such as steel, aluminum and the like, by any of the conventional methods employed by the coating industry. In the coating of the metal sheet used in container fabrication, gravure coating is the preferred method, as the desired coating configuration and weight is easily and conveniently applied in a single coat.

The applied coating 24 after substantially volatile loss of the solvent is cured to a hard film by heating the coated substrate at a temperature between about 150 and about 230C for about 1 to minutes. The preferred coating weight for coating metal sheet substrates with an adequately protective coating for use as an enamel for containers is in the range of about lto 10 milligrams of dry coating per square inch of substrate surfacefAs shown, the coating 24 is applied to provide an annular band or strip 26 of exposed metal which spans the weakening line 17. The plastisol ring 22 is then applied, as more fully to be explained hereinafter, so as to be adhered to the opposite marginal portions of the coating 24 bounding the bare metal annular band 26 as shown.

The plastisol composition is made up of .a vinyl resin and plasticizers to create the desired pliability and hardness characteristics in connection with the pliability and hardness of the band member 22. It should be mentioned that the band material must be sufficiently pliable to yield during the initial rupturing of the weakening line as shown in FIG. 4 and at the same time be sufiiciently hard to provide a protective ledge projecting outwardly of the edge 23.

In carrying out the present invention, any conventional plastisol composition may be used. The term plastisol refers to dispersions of finely divided thermoplastic resin particles in a liquid nonvolatile plasticizer in which the resin is insoluble or only very slightly soluble at room temperature. However, at elevated temperatures, the resin is solvated by the plasticizer'so that a homogeneous mass is obtained which forms a rubbery thermoplastic solid upon cooling. In addition to the resin and plasticizer, the composition may also contain fillers, pigments, stabilizers, and various other conventional compounding ingredients.

Typical of the plastisol compositions which may be used are those containing 100 parts by weight of a vinyl chloride polymer, between about 25 and partsby weight plasticizer and about 0 to 50 partsby weight filler. When stabilizers, wetting agents, and other ingredients are employed, they are used in conventional amounts to achieve the desired effect. Among'the resins which may be employed in the present invention are any of the plastisol grade resins commonly used in the plastisol art and conventionally preparedby emulsion polymerization techniques. Such resins include high molecular weight homopolymers of vinyl chloride and copolymers of vinyl chloride with up to 20 percent, and preferably less than 10 percent,'of acrylonitrile, vinylidene chloride, vinyl acetate, dialkyl maleates or other monomer copolymeri zable therewith. Suitable plastisol grade resins which are homopolymers of vinyl chloride include Geon l2l, Exon 654, Marvionol VR-50 and the like. Other plastisol grade resins which may be employed are PVC-74, a copolymer of 97 percent vinyl chloride and 3 vinyl acetate, and Pliovic A0, a copolymer of percent vinyl chloride and 5 percent dialkyl maleate. Also useful are blends of plastisol resins with suspension grade resins which are prepared by suspension polymerization techniques. The suspension grade resins like the plastisol resins may be homopolymers'of vinyl chloride such as Pliovic M-90, Marvinol VR-lO, and Geon 101 or copolymers of vinyl chloride containing minor amounts of comonomer. Examples of suitable suspension grade resins which are copolymers of vinyl chloride include Geon 202 (94 percent vinyl chloride copolymerized with 6 percent vinylidene chloride), and VC2 65 (95 percent vinyl chloride copolymerized with 5 percent vinyl acetate).

Among the plasticizers which may be used in preparing the plastisol composition are dialkyl phthalates, alkyl phthalyl, alkyl glycolates, dialkyl esters of alkane dicarboxylic acids, acetyl trialkyl citrates, and epoxidized triglycerides. Particular plasticizers which may be employed include dioctyl phthalate, dioctyl adipate, dioctyl sebacate, acetayl tributyl citrate and butyl phthalyl butyl glycolate. Other useful plasticizers include epoxidized soybean oil, and polymeric polyester plasticizers, e.g., polyethylene glycol adipate. While many of the primary plasticizers may be employed, mixtures of primary plasticizers and mixtures of one or more primary plasticizers with one or more secondary plasticizers may be employed.

Other ingredients which may be incorporated into the plastisols,'if desired, are fillers, e.g., whiting, talc, clays, barytes, asbestine; pigments, e.g., carbon black, iron oxide, aluminum powder and titanium dioxide; stabilizers, e.g., epoxidized oils, zinc and calcium stearates and wetting agents, e.g., zinc resinate, polyethylene glycol fatty acid esters, and lecithin.

In the preparation of the plastisol composition, the resin was added to the plasticizer in small increments while stirring at low speeds. After resin addition was complete, the stabilizers were added, and stirring continued until a homogeneous blend was obtained. Prior to lining, the composition was deaerated fora short ti- An example of a plastisol composition employed for the present invention is as follows:

The above composition was applied to the can ends by spin lining using standard automatic nozzle-lining equipment to form the ring 22 as shown in FIGS. 3-5.

After lining, the end units with the plastisol ring are conveyed through an even where fusion of the plastisol is achieved at conventional temperatures, e.g., in the range of 175 to 200C for a time sufiicient to permit complete solvation of the resin.

Physical properties of the fusedv plastisol baked at 190C for 3 minutes were as follows:

Elongation 75 Tensile, psi l973 Hardness, Shore A The plastisol band 22 ranges in thickness from about 0.010 to 0.020 inches. It is to be particularly noted that the plastisol band 22 overlies the peripheral marginal portion of the vinyl resin coating 24 while the inner circurnference thereof abuts against the opposite coating edge and does not adhere to the bare metal of the end closure 16 but merely is in intimate contact therewith. Thus, the band 22 is only bonded to the opposite marginal edge portions of the coating 24 bounding the bare metal strip 26.

When the pull tab 21 is initially lifted as shown in FIG. 4, the nose thereof is operative to sever the end closure along the weakening line 17 and break the bond at the inner marginal edge of the ring 22 with the coating 24 so that the ring 22 separates therefrom.

However, the ring 22 remains attached at its opposite end so that the ring is tilted downwardly at an inclined angle as shown. Upon complete removal of the removable panel portion 18 from the opening, the plastisol which is resilient and pliable returns to a substantially horizontal position projecting beyond the outer edge 23 remaining on the container end 16. In this manner, the ring 22 provides a protective ledge and prevents a hand or other objects from contacting the raw edge on the panel. It is also to be observed that when the plastisol ring 22 is applied, it provides a protective barrier beneath the score line and retards corrosion at the bare metal interface so as to protect the weakening line and prevent inadvertent fracture.

Referring now to FIG. 6, a flexible band 30 is shown applied to the upper side of the container end closure 12 for removal with the removable panel portion 18. The band 30 is applied to provide a protective ledge for the edge of the separated removable panel portion.

As shown, the upper side of the end closure 12 is also provided with the enamel coating 240 similar to the coating 24 on the underside thereof. The enamel coating 24a is applied in the same manner as described heretofore to define an exposed metal strip 26a.

The flexible plastisol band 30 is the same composition as the band 22 and is applied in the same manner..

It is to be noted, however, that the flexible band 30 overlies the enamel coating 24 on the removable panel portion 18 so as to be adheredthereto. Along the outer edge, the flexible band 30 lies adjacent the enamel coating 24a on the ledge of the endclosure.

Upon removal of the removable panel'portion, the pull tab 21 is tilted upwardly, to initially sever the weakening line 17 as described in connection with FIGS. 1-5. During the initial severance, the flexible band 30 yields and is separated from the coating 24a on the ledge but remains adhered to the coating on the removable panel 18. Upon upward pulling to complete the separation of the removable panel portion 18, the band 30 remains adhered thereto and extends beyond the edge. In this manner the band protects the sharp edge of the removal panel 18.

Referring now to FIG. 7, optionally, as when the container 10 is to be used to package a food product which could have a corrosive effect on the strip 26 of exposed bare metal, a base coating 24b is first applied to the entire surface on the underside of the metal end panel 16, including the uncoated, bare metal strip 26, before the application of the enamel coating 24. The base coating 24b is prepared from a thermosetting resin composition to which the enamel coating 24 is adherent and to which the plastisol annular ring 22 is nonadherent.

The materials from which the thermosetting base coating 24b is prepared are conventional in the art and include epoxy resins, phenolic resins, amine/aldehyde resins and mixtures thereof.

Typical epoxy resins which may be employed in coating formulations of which base coating 24b is comprised include epoxy resins of the type which are polymeric reaction products of polyfunctional halohydrins with polyhydric phenols having the structural formula:

wherein at represents the number of molecules condensed.

Typical polyfunctional halohydrins are epicholochydrin, glycerol dichlorohydrin and the like. Typical polyhydric phenols are resorcinol and a 2,2-bis (4- hydroxyphenyl) alkane, the latter resulting from the condensation of phenols with aldehydes and ketones, including formaldehye, acetaldehyde, propionaldehyde, acetone, methyl ethyl ketone and the like, which result in such compounds as 2,2-bis (4- hydroxyphenyl) propane and the like compounds. These epoxy resins normally contain terminal epoxy groups but may contain terminal epoxy groups and terminal hydroxyl groups.

In place of or in admixture with the epoxy resins, any of the well known class of heat hardenable phenolic resins produced by condensing a phenolic compound with an aldehydic compound may be employed as the thermosetting base coating 24b.

The thermosetting phenolic resin preferably consists of a phenol/aldehyde resin advanced in its condensation to an intermediate condition or B-stage in which the resin is water insoluble, but soluble in selected organic solvents and capable of further reaction under the influence of heat, into the insoluble or C stage.

Exemplary phenols suitable for the preparation of phenol-formaldehyde resins include phenol itself, the ortho-para-and meta-cresols, the xylenols, the dihydroxy benzenes, such as resorcinol, the polynuclear phenols such as the naphthols, and the various alkylated, aralkylated, carboxylated, alkyloated,'etc., derivatives of these types, such as o-ethyl phenol, carva-crol, salicylic acid and thelike.

Formaldehyde is the aldehydic compound preferred for condensation with the phenolic compound, but in general any methylene-containing agent, such as formaldehyde, paraformaldehyde, hexamethylene tetramine, acetaldehyde, and the like may be used.

Amine-aldehyde resins may also be employed in preparing the thermosetting base coating 24b either separately or in combination with epoxy and/r phenolic resins. I

The term amine-aldehyde resin includes aldehyde condensation products of melamine, urea, acetoguanamine, or a similar compound. Generally, the aldehyde employed is formaldehyde, although useful products can be made from other aldehydes, such as acetaldehyde, crotronaldehyde, acrolein, benzaldehyde, furfural, and others. Condensation products of melamine or urea are the commonly employed aminealdehyde resins.

The thermosetting base coating 24b is applied to the underside of the metal end panel in the same manner as the enamel coating 24 except that the base coating 24b is applied to the entire underside of the panel 16 including the annular band area 26 which spans the weakening line 17.

After the application of the base coating 24b the enamel coating 24 is applied to the coated underside of the panel 16 except in the area of the panel 16 encompassed by the strip 26 spanning the weakening line 17. In this manner the plastisol ring 22 will adhere to the enamel coating 24 but will not adhere to the strip 26 coated with base coating 24b.

I claim:

1. An easy opening container including an end having a metal end panel, a weakening line formed by scoring at least one face of said end panel, said weakening line defining a removable panel portion, a coating applied on at least one face of said end panel, said weakening line defining a removablepanel portion, a coating applied on at least one face of said end panel, said coating having spaced exposed portions on opposite sides of a strip on the coatedface generallyaligned with and spanning that portion of said end panel containing said weakening line, and a plastic band spanning said strip and adhered along one of said coating edge portions and releasable from the other of said coating edge portions, said strip exhibiting a low afiinity for said plastic band as compared to said coating exposed edge portrons.

2. The invention as defined in claim 1 wherein said plastic band is a plastisol.

3. The invention as defined in claim 2 wherein said band comprises a polyvinylchloride based plastisol.

4. The invention as defined in claim 3 wherein said polyvinylchloride based plastisol is applied on said one face selectively by spin-lining and spot-coating methods.

5. The invention as defined in claim 4 wherein said polyvinylchloride based plastisol is flexible to permit displacement of said removable panel portion inwardly and sufficiently hard to provide a ledge preventing contact with the edge remaining on said end when said removable panel is separated therefrom along said weakening line.

6. The invention as defined in claim 1 wherein said I coating is applied on the underside of said end panel and said plastic band is disposed on the underside of said panel and adhered to the marginal edge of said coating opposite the removable panel portion.

7. The invention as defined in claim 1 wherein said coating is applied on the upper side of said end panel and said plastic band is disposed on the upperside of said panel and adhered to the marginal edge of said coating on said removable panel portion so as to be removable therewith.

8. The invention as defined in claim 1 wherein said coating is applied on both sides of said end panel, and wherein a plastic band is disposedon each side of said end panel with the band on said-upper side being adhered to the marginal edge portion of the respective coating on said removable panel portion, and with the band on the underside being adhered to the outer marginal edge portion of the respective coating.

9. The invention as defined in claim 1 wherein the coating is a protective coating applied over a base coating applied to the underside face of the end panel including said strip, the plastic band is disposed on the underside face of the panel and is adherent to the marginal edge portion of the protective coating and is nonadherent to the exposed base coating strip.

10. The invention as defined in claim 9 wherein 'said base coating is a thermosetting coating.

11. The invention as defined in claim 9 wherein said base coating is a thermosetting coating and said protective coating is an enamel coating.

12. The invention as defined in claim 1 wherein said strip has a thermosetting coating.

14. The invention as defined in claim 1 wherein said strip has a thermosetting coating which extends beneath the first mentioned coating. 

1. An easy opening container including an end having a metal end panel, a weakening line formed by scoring at least one face of said end panel, said weakening line defining a removable panel portion, a coating applied on at least one face of said end panel, said weakening line defining a removable panel portion, a coating applied on at least one face of said end panel, said coating having spaced exposed portions on opposite sides of a strip on the coated face generally aligned with and spanning that portion of said end panel containing said weakening line, and a plastic band spanning said strip and adhered along one of said coating edge portions and releasable from the other of said coating edge portions, said strip exhibiting a low affinity for said plastic band as compared to said coating exposed edge portions.
 2. The invention as defined in claim 1 wherein said plastic band is a plastisol.
 3. The invention as defined in claim 2 wherein said band comprises a polyvinylchloride based plastisol.
 4. The invention as defined in claim 3 wherein said polyvinylchloride based plastisol is applied on said one face selectively by spin-lining and spot-coating methods.
 5. The invention as defined in claim 4 wherein said polyvinylchloride based plastisol is flexible to permit displacement of said removable panel portion inwardly and sufficiently hard to provide a ledge preventing contact with the edge remaining on said end when said removable panel is separated therefrom along said weakening line.
 6. The invention as defined in claim 1 wherein said coating is applied on the underside of said end panel and said plastic band is disposed on the underside of said panel and adhered to the marginal edge of said coating opposite the removable panel portion.
 7. The invention as defined in claim 1 wherein said coating is applied on the upper side of said end panel and said plastic band is disposed on the upperside of said panel and adhered to the marginal edge of said coating on said removable panel portion so as to be removable therewith.
 8. The invention as defined in claim 1 wherein said coating is applied on both sides of said end panel, and wherein a plastic band is disposed on each side of said end panel with the band on said upper side being adhered to the marginal edge portion of the respective coating on said removable panel portion, and with the band on the underside being adhered to the outer marginal edge portion of the respective coating.
 9. The invention as defined in claim 1 wherein the coating is a protective coating applied over a base coating applied to the underside face of the end panel including said strip, the plastic band is disposed on the underside face of the panel and is adherent to the marginal edge portion of the protective coating and is nonadherent to the exposed base coating strip.
 10. The invention as defined in claim 9 wherein said base coating is a thermosetting coating.
 11. The invention as defined in claim 9 wherein said base coating is a thermosetting coating and said protective coating is an enamel coating.
 12. The invention as defined in claim 1 wherein said strip is of bare metal.
 13. The invention as defined in claim 1 wherein said strip has a thermosetting coating.
 14. The invention as defined in claim 1 wherein said strip has a thermosetting coating which extends beneath the first mentioned coating. 